(1) Field of the Invention
The invention is related to a rotor blade with at least one control flap with the features of the preamble of claim 1.
(2) Description of Related Art
The control flap is intended to enable individual blade control. For a rotor blade with a control flap an actuator is necessary to control the flap.
The document U.S. Pat. No. 5,811,911 discloses a piezoelectric actuator with at least two disk-shaped congruent bending elements which each have a carrier plate made of a hard-elastic material with a layer of a piezoelectric material applied to one or both sides. Two bending elements respectively are connected with one another by way of at least two bending joints arranged on the circumference of the carrier plates.
The document DE 100 17 332 A1 discloses a piezoelectric actuating device for controlling the flaps on the rotor blade of a helicopter. The device comprises a piezo element arrangement and a power transmission frame which is coupled therewith, is fixed to the rotor blade and generates a force between an abutment and a driven element by changing the length of the piezo element arrangement. Said force is effective crosswise in relation to the direction of the centrifugal force of the rotor blade.
The document US 2002/0071767 A1 discloses a rotor blade arrangement with a rotor blade, a hollow blade chamber therein, and a flap module removably arranged and secured in the blade chamber. The flap module includes a module housing received in the blade chamber, an actuator arranged in the housing, a flap pivotably arranged at an edge of the housing, and a power transmission linkage connecting the actuator to the flap. The flap may be a trailing edge flap at the trailing edge of the blade. The entire flap module can be easily removed from the blade for adjustment, inspection, maintenance, repair or replacement.
The document EP 2 514 669 A1 discloses a gurney-type flap assembly in which an actuator is connected to the flap via an actuator output and a yolk assembly.
In document U.S. Pat. No. 6,196,796 B1 there is an actuator which controls the flap by means of two supply lines (one used to move the flap upwards, the other to move it downwards) so that depending on which supply line is active certain lobes of a butterfly shaft pressurize or depressurize, thus controlling the torque exerted on the flap.
The document EP 1 035 015 A2 describes an actuator housed in a rotor blade. The actuator is in contact with four thin plates of a “displacement magnifying means—its contraction and expansion moves such plates, which in turn transmit this “magnified displacement” to the flap.
In document US 2002/0141867 A1, the actuator is connected to the flap by means of two parallel tension struts, both of them located in the plane in which the flap itself extends.